Vibrational catheter devices and methods for making same

ABSTRACT

A vibrational catheter for disrupting obstructions in lumens such as blood vessels includes an elongate flexible catheter body having a proximal end, a distal end and at least one lumen extending longitudinally therethrough, a vibrational transmission member extending longitudinally through the lumen of the catheter body and having a proximal end and a distal end, and a transition connector attached to the proximal end of the vibrational transmission member for coupling the transmission member with a vibrational energy source. The transition connector includes a bore into which the proximal end of the vibrational transmission member extends. The proximal end of the vibrational transmission member is attached within the bore of the transition connector with variable attachment forces such that the transition connector exerts a lowest amount of attachment force on an attached distal-most portion of the vibrational transmission member housed within the bore.

This application is related to the following U.S. patent applicationSer. No. 10/229,371, filed Aug. 26, 2002, entitled “Ultrasound Catheterfor Disrupting Blood Vessel Obstructions” (Attorney Docket No.021577-000400US); Ser. No. 10/345,078, filed Jan. 14, 2003, entitled“Ultrasound Catheter and Methods for Making and Using Same” (AttorneyDocket No. 021577-000600US); Ser. No. 10/375,903, filed Feb. 26, 2003,entitled “Ultrasound Catheter Apparatus” (Attorney Docket No.021577-000700US); Ser. No. 10/410,617, filed Apr. 8, 2003, entitled“Improved Ultrasound Catheter Devices and Methods” (Attorney Docket No.021577-000800US); Ser. No. 10/722,209, filed Nov. 24, 2003, entitled“Steerable Ultrasound Catheter” (Attorney Docket No. 021577-000900US)and Ser. No. 10/927,966, filed Aug. 26, 2004, entitled “ImprovedUltrasound Catheter Devices and Methods” (Attorney Docket No.021577-001000US). The full disclosures of all of the above-listed patentapplications are all hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to medical devices and methods.More specifically, the present invention relates to vibrational catheterdevices and methods for treating occlusive intravascular lesions.

Catheters employing various types of vibration transmitting members havebeen successfully used to ablate or otherwise disrupt obstructions inblood vessels. Specifically, ablation of atherosclerotic plaque orthromboembolic obstructions from peripheral blood vessels such as thefemoral arteries has been particularly successful. Various vibrationalcatheter devices have been developed for use in ablating or otherwiseremoving obstructive material from blood vessels. For example, U.S. Pat.Nos. 5,267,954 and 5,380,274, issued to an inventor of the presentinvention and hereby incorporated by reference, describe ultrasoundcatheter devices for removing occlusions. Other examples of ultrasonicablation devices for removing obstructions from blood vessels includethose described in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman,et al.), 4,808,153 (Parisi), 4,936,281 3,565,062 (Kuris), 4,924,863(Sterzer), 4,870,953 (Don Michael, et al), and 4,920,954 (Alliger, etal.), as well as other patent publications WO87-05739 (Cooper),WO89-06515 (Bernstein, et al.), WO90-0130 (Sonic Needle Corp.), EP316789(Don Michael, et al.), DE3,821,836 (Schubert) and DE2438648 (Pohlman).While many vibrational catheters have been developed, however,improvements are still being pursued.

Typically, a vibrational catheter system for ablating occlusive materialincludes three basic components: an vibration energy generator, atransducer, and a vibrational catheter. The generator converts linepower into a high frequency current that is delivered to the transducer.The transducer contains piezoelectric crystals which, when excited bythe high frequency current, expand and contract at high frequency. Thesesmall, high-frequency expansions (relative to an axis of the transducerand the catheter) are amplified by the transducer horn into vibrationalenergy. The vibrations are then transmitted from the transducer throughthe vibrational catheter via a vibrational transmission member (orwire). The transmission member transmits the vibrational energy to thedistal end of the catheter where the energy is used to ablate orotherwise disrupt a vascular obstruction.

To effectively reach various sites for treatment of intravascularocclusions, vibrational catheters of the type described above typicallyhave lengths of about 150 cm or longer. To permit the advancement ofsuch vibrational catheters through small and/or tortuous blood vesselssuch as the aortic arch, coronary vessels, and peripheral vasculature ofthe lower extremities, the catheters (and their respective ultrasoundtransmission wires) must typically be sufficiently small and flexible.Also, due to attenuation of ultrasound energy along the long, thin,ultrasound transmission wire, a sufficient amount of vibrational energymust be applied at the proximal end of the wire to provide a desiredamount of energy at the distal end.

One continuing challenge in developing vibrational catheters fortreating vascular occlusions is to provide adequate vibrational energyat the distal end of a catheter device while simultaneously minimizingstress on the vibrational transmission wire in the area where itconnects with the transducer. Typically, the vibrational transmissionwire is coupled with the transducer via some kind of connector. Aportion of the transmission wire immediately adjacent the connector isoften put under great stress and strain when sufficient vibrationalenergy is applied to provide the desired vibration at the distal end ofthe catheter. This stress and strain can cause overheating and unwantedwear and tear of the transmission member, thus leading to wire breakageand a shortened useful life of the catheter device.

Some vibrational catheter devices include one or more absorption memberswhere the proximal end of the vibrational transmission wire attaches toa transducer connector. For example, one such absorption member isdescribed in U.S. Pat. No. 5,382,228. Such absorption members, however,may have drawbacks, in that they may be prone to coming loose anddisconnecting from the transducer connector, and would thus become aloosely moving body within the catheter, disrupting vibrational energytransmission and reducing the catheter's efficacy.

Therefore, a need exists for improved vibrational catheter devices andmethods that provide ablation and/or disruption of obstructions inlumens, such as vascular lumens. Ideally, such vibrational catheterswould provide a desired level of power at a distal end of the devicewhile also preventing or reducing stress and strain placed on theproximal end of the vibrational transmission member. Also ideally, suchdevices would be easily manufactured and have as few moving parts aspossible in the area of connection of the transmission member with thetransducer connector. At least some of these objectives will be met bythe present invention.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a vibrational catheter fordisrupting obstructions in lumens such as blood vessels includes anelongate flexible catheter body having a proximal end, a distal end andat least one lumen extending longitudinally therethrough, a vibrationaltransmission member extending longitudinally through the lumen of thecatheter body and having a proximal end and a distal end, and atransition connector attached to the proximal end of the vibrationaltransmission member for coupling the transmission member with avibrational energy source. The transition connector includes a bore intowhich the proximal end of the vibrational transmission member extends.The proximal end of the vibrational transmission member is attachedwithin the bore of the transition connector with variable attachmentforces such that the transition connector exerts a lowest amount ofattachment force on an attached distal-most portion of the vibrationaltransmission member housed within the bore.

In some embodiments, the vibrational energy source comprises atransducer, such as but not limited to an ultrasound transducer. In someembodiments, the transition connector may comprise multiple piecesattached together, while in other embodiments the transition connectorcomprises a one-piece extrusion. In one embodiment, the proximalconnection member of the transition connector comprises threads, whichare complementary to threads on the vibrational energy source.Alternatively, any other suitable connection device may be used.

In some embodiments, the transition connector comprises a distal portiontapered proximally to distally, the distal portion extending from aproximal terminus of the bore to the opening of the bore. In suchembodiments, the vibrational transmission member may be attached withinthe bore by crimping the tapered distal portion of the transitionconnector so as to apply greater crimping force to a wider, proximalportion of the distal portion than to a narrower, distal portion of thedistal portion. In alternative embodiments, the transition connectorcomprises a distal portion including a first stepped portion having afirst radius and extending distally from a proximal terminus of the boreand a second stepped portion having a second radius smaller than thefirst radius and extending from a distal end of the first steppedportion to the distal opening of the bore. In these latter embodiments,the vibrational transmission member may be attached within the bore bycrimping the first stepped portion, thus applying greater crimping forceto the first stepped portion than the second stepped portion.

In another alternative embodiment, the bore comprises a first steppedportion having a first radius and extending distally from a proximalterminus of the bore and a second stepped portion having a second radiusgreater than the first radius and extending from a distal end of thefirst stepped portion to the distal opening of the bore. Optionally, insuch an embodiment, the vibrational transmission member may be attachedwithin the bore by crimping the transition connector, thus applyinggreater crimping force to the first stepped portion than the secondstepped portion. In some cases, a space exists between the transmissionmember and the second stepped portion of the bore before crimping, andthe space closes during crimping.

In another aspect of the present invention, a vibrational catheter fordisrupting obstructions in lumens such as blood vessels includes anelongate flexible catheter body having a proximal end, a distal end andat least one lumen extending longitudinally therethrough, a vibrationaltransmission member extending longitudinally through the lumen of thecatheter body and having a proximal end and a distal end, and atransition connector. The transition connector includes a proximalconnection member for attaching the transition connector to avibrational energy source and a bore having an opening in a distal endof, and extending into, the transition connector, for accepting theproximal end of the vibrational transmission member. The proximal end ofthe vibrational transmission member extends into and is attached withinthe distal bore of the transition connector such that the transitionconnector exerts a greater amount of attachment force on an attachedproximal-most portion of the transmission member than on an adjacentportion of the transmission member immediately distal to theproximal-most portion. Various embodiments of this catheter may includeany of the features described above.

In another aspect of the present invention, a method for making avibrational catheter for disrupting obstructions in lumens such as bloodvessels includes inserting a proximal end of a vibrational transmissionmember into a bore in a transition connector and crimping at least partof the transition connector to attach the proximal end of thevibrational transmission member within the bore. In this method, avariable amount of crimping force is applied to attach the vibrationaltransmission member within the bore, so that the transition connectorexerts a lowest amount of attachment force on an attached distal-mostportion of the vibrational transmission member housed within the bore.

In some embodiments, crimping is performed with a crimping tool having acontact surface parallel with the vibrational transmission member, andthe greater amount of crimping force is applied via a shaped portion ofthe transition connector overlying the bore. In alternative embodiments,crimping is performed with a crimping tool having a contact surfaceparallel with the vibrational transmission member, and the greateramount of crimping force is applied via a shaped bore. In anotheralternative embodiment, crimping is performed with a tapered crimpingtool having a contact surface that contacts a proximal portion of thetransition connector overlying the bore before contacting a more distalportion of the transition connector overlying the bore. Alternatively,crimping may performed with two crimping members, a more proximalcrimping member applying greater force than a more distal crimpingmember. In another alternative embodiment, crimping involves crimping afirst portion of the transition connector overlying the proximal-mostportion of the transmission member with a crimping tool, moving thecrimping tool distally along the transition connector, and crimping asecond portion of the transition connector overlying the adjacentportion of the transmission member.

These and other aspects and embodiments of the present invention aredescribed in further detail below, in reference to the attached drawingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vibrational catheter system, accordingto an embodiment of the present invention;

FIG. 2 is a side view of a vibrational catheter device, according to anembodiment of the present invention;

FIG. 3 is cross-sectional side view of a proximal portion of avibrational catheter device having heat dissipation means, according toan embodiment of the present invention;

FIGS. 4A and 4B are cross-sectional side views of a proximal portion ofa vibrational transmission member coupled with a transition connectorfor connecting to a vibrational energy source, according to anembodiment of the present invention;

FIG. 4C is a perspective view of the vibrational transmission member andtransition connector of FIGS. 4A and 4B;

FIGS. 5A and 5B are cross-sectional side views of a proximal portion ofa vibrational transmission member coupled with a transition connectorfor connecting to a vibrational energy source, according to analternative embodiment of the present invention;

FIG. 5C is a perspective view of the vibrational transmission member andtransition connector of FIGS. 5A and 5B;

FIGS. 6A and 6B are cross-sectional side views of a proximal portion ofa vibrational transmission member coupled with a transition connectorfor connecting to a vibrational energy source, according to analternative embodiment of the present invention;

FIG. 6C is a perspective view of the vibrational transmission member andtransition connector of FIGS. 6A and 6B;

FIGS. 7A and 7B are cross-sectional side views of a proximal portion ofa vibrational transmission member coupled with a transition connectorfor connecting to a vibrational energy source, according to analternative embodiment of the present invention;

FIGS. 8A and 8B are cross-sectional side views of a proximal portion ofa vibrational transmission member coupled with a transition connectorfor connecting to a vibrational energy source, according to analternative embodiment of the present invention; and

FIG. 8C is a perspective view of the vibrational transmission member andtransition connector of FIGS. 8A and 8B.

DETAILED DESCRIPTION OF THE INVENTION

Vibrational catheter devices and methods of the present inventionprovide for disruption of occlusions in blood vessels. The vibrationalcatheter devices generally include a catheter body, a vibrational energytransmission member disposed within the catheter body, and a distal headcoupled with the vibrational transmission member and disposed at or nearthe distal end of the catheter body. The vibrational transmission membertransmits vibrational energy, such as ultrasound energy, from a proximalvibrational energy source, such as an ultrasound transducer, to thedistal head, causing the head to vibrate and, thus, disrupt vascularocclusions. A number of features of such vibrational catheter devicesare described more fully below.

Referring now to FIG. 1, one embodiment of a vibrational catheter system20 suitably includes a vibrational catheter device 10 and a vibrationalenergy generator 16. Catheter device 10 suitably includes a distal head26 for disrupting occlusions, a catheter body 27, and a proximal endknob 12 for coupling catheter device 10 with a vibrational energytransducer 14. Vibrational energy transducer 14 is coupled withultrasound generator 16 via a connector 28, and generator is coupledwith a foot-actuated on/off switch 18 via another connector 29.Generator 16 provides vibrational energy to transducer 14 and, thus, tovibrational catheter 10. Catheter device 10 further includes avibrational transmission member (or “wire”—not shown) that extendsthrough the catheter body 27 and transmits energy from the transducer 14to the distal head 26. Some embodiments of device 10 include a rapidexchange guidewire 13 and guidewire port, while other embodimentsinclude a proximal guidewire port for over the wire guidewire delivery.In some embodiments, transducer 14 further includes a securing device 15for enhancing coupling of catheter 10 to transducer 14. The variouscomponents of system 20 may be coupled via any suitable means.Connectors 28, 29 may comprise an electric cord or cable or any othersuitable connecting devices for coupling on/off switch 18, generator 16and transducer 14. In an alternative embodiment, on/off swith 18 islocated on generator 16.

In addition to proximal knob 12, vibrational catheter device 10 mayinclude one or more other various components, such as a Y-connector 11including a fluid inlet port 17 (or aperture) for passage of irrigationfluid. Inlet port 17 may be removably coupled with an irrigation tube24, which in one embodiment may be coupled with a fluid refrigeration(or “fluid cooling”) device 30. Refrigeration device 30 may, in turn, becoupled with a fluid container 32 via a connector tube 34. Thisirrigation apparatus may be used for introducing one or more fluids intocatheter device 10. Fluid may be used to cool any part of the device,such as the vibrational transmission member, thus helping reduce wearand tear of device 10. In some embodiments, fluid inlet port 17 islocated farther proximally on proximal knob 12, to allow fluid to beapplied within knob 12. In some embodiments, refrigerated fluid is used,while in other embodiments irrigation fluid may be kept at roomtemperature. In various embodiments, oxygen supersaturated fluid,lubricious fluid, or any other suitable fluid or combination of fluidsmay be used, and again, such fluids may be refrigerated or kept roomtemperature. In an alternative embodiment to that shown in FIG. 1,refrigeration device 30 and fluid container 32 are combined in onedevice.

Generally, catheter device 10 may include any suitable number ofside-arms or ports for passage of a guidewire, application of suction,infusing and/or withdrawing irrigation fluid, dye and/or the like, orany other suitable ports or connections. Also, vibrational catheters 10of the present invention may be used with any suitable proximal devices,such as any suitable transducer 14, generator 16, coupling device(s)and/or the like. Therefore, the exemplary embodiment shown in FIG. 1 andany following descriptions of proximal apparatus or systems for use withvibrational catheters 10 should not be interpreted to limit the scope ofthe present invention as defined in the appended claims.

Referring now to FIG. 2, an enlarged view of catheter device 10 isshown. Proximal knob 12, Y-connector 11, inlet port 17, catheter body27, distal head 26 and guidewire 13 are all shown. Catheter body 27 isgenerally a flexible, tubular, elongate member, having any suitablediameter and length for reaching a vascular occlusion for treatment. Inone embodiment, for example, catheter body 27 preferably has an outerdiameter of between about 0.5 mm and about 5.0 mm. In other embodiments,as in catheters intended for use in relatively small vessels, catheterbody 27 may have an outer diameter of between about 0.25 mm and about2.5 mm. Catheter body 27 may also have any suitable length. As discussedbriefly above, for example, some vibrational catheters 10 have a lengthin the range of about 150 cm. However, any other suitable length may beused without departing from the scope of the present invention. Examplesof catheter bodies similar to those which may be used in the presentinvention are described in U.S. Pat. Nos. 5,267,954 and 5,989,208, whichwere previously incorporated herein by reference.

Features of the present invention may be applied to any of a number ofvibrational catheter devices. For more detailed description of exemplaryvibrational catheter devices, reference may be made to U.S. patentapplication Ser. Nos. 10/229,371, 10/345,078, 10/375,903, 10/410,617,10/722,209 and 0/927,966, which were all previously incorporated byreference. In various alternative embodiments, aspects of the presentinvention may be applied to any other suitable catheter devices.

Referring now to FIG. 3, a proximal portion of one embodiment of avibrational catheter device 110 is shown in cross-section. An ultrasoundtransmission wire 140 extends from a transition connector 152 distallyto a distal end (not shown) of catheter device 110. A catheter body 127of device 110 is shown only in part, whereas catheter body 127 typicallyextends distally to (or near) the distal end of device 110. Catheterdevice 110 also includes a proximal knob 112 (or “housing”), having aninner bore 144 in which transition connector 152, a portion ofvibrational transmission member 140 and one or more vibration absorptionmembers 150 reside. Knob 112 is coupled with a Y-connector 111, whichincludes a fluid inlet port 117 (or aperture), and Y-connector 111 iscoupled with catheter body 127.

In various embodiments, knob 112 may suitably include one or moresurface features 142 for increasing the overall surface area of theouter surface of knob 112. Increased surface area enhances the abilityof knob 112 to dissipate heat generated by vibrational transmissionmember 140 out of catheter device 110. Surface features 142 may have anysuitable size or shape, such as ridges, jags, undulations, grooves orthe like, and any suitable number of surface features 142 may be used.Additionally, knob 112 may be made of one or more heat dissipatingmaterials, such as aluminum, stainless steel, any other conductivemetal(s), or any suitable non-metallic conductive material(s).

In most embodiments, vibrational transmission member 140, wire, or waveguide extends longitudinally through a lumen of catheter body 127 totransmit vibrational energy from a transducer (not shown), connected tothe proximal end of proximal knob 112, to the distal end of catheterdevice 110. Vibrational transmission member 140 may be formed of anymaterial capable of effectively transmitting vibrational energy from thetransducer, such as an ultrasound transducer, to the distal end ofcatheter body 127, including but not limited to metals such as puretitanium or aluminum, or titanium or aluminum alloys. Again, additionaldetails of vibrational transmission members 140 may be found in thepatent applications incorporated by reference above. Similarly,reference may be made to the incorporated patent applications fordescriptions of knob 112, transition connector 152, vibration absorptionmembers 150, Y-connector 111 and the like. For example, knob 112 andother features are described in detail in U.S. patent application Ser.No. 10/722,209, which was previously incorporated by reference.

Vibrational transmission member 140 typically passes from transitionconnector 152, through bore 144 and Y-connector 111, and then throughcatheter body 127. Fluid inlet port 117 is in fluid communication with alumen in Y-connector, which is in fluid communication with a lumenextending through catheter body 127. Thus, fluid introduced into fluidinlet port 117 is typically free to flow into and through catheter body127 to contact vibrational transmission member 140. Fluid may flow outof catheter body 127 through apertures in the distal head (not shown) orthrough any other suitable apertures or openings, such as apertureslocated in catheter body 127 itself. Any suitable fluid may be passedthrough fluid inlet port 117 and catheter body 127, such as refrigeratedfluid, lubricious fluid, super-saturated saline or contrast/salinemixture, or the like. Cooling and/or lubricating vibrationaltransmission member 140 may reduce friction and/or wear and tear ofvibrational transmission member 140, thus prolonging the useful life ofvibrational catheter device 110 and enhancing its performance.

Additionally, the temperature and flow rate of a coolant liquid may bespecifically controlled to maintain the temperature of vibrationaltransmission member 140 at a desired temperature within its optimalworking range. In particular, in embodiments of the invention wherevibrational transmission member 140 is formed of a metal alloy whichexhibits optimal physical properties (e.g. super elasticity) within aspecific range of temperatures, the temperature and flow rate of coolantliquid infused through fluid inlet port 117 may be specificallycontrolled to maintain the temperature of vibrational transmissionmember 140 within a range of temperatures at which it demonstrates itsmost desirable physical properties. For example, in embodiments of theinvention where vibrational transmission member 140 is formed of a shapememory alloy which exhibits super-elasticity when in its martensitestate, but which loses super-elasticity as it transitions to anaustenite state, it will be desirable to adjust the temperature and flowrate of the coolant liquid infused through fluid inlet port 117 tomaintain the shape memory alloy of vibrational transmission member 140within a temperature range at which the alloy will remain in itsmartensite state and will not transition to an austenite state. Thetemperature at which such shape memory alloys transition from amartensite state to an austenite state is known as the “martensitetransition temperature” of the material. Thus, in these embodiments, thefluid infused through port 117 will be at such temperature, and will beinfused at such rate, as to maintain the shape memory alloy ofvibrational transmission member 140 below its martensite transitiontemperature.

As mentioned above, in one embodiment, a super-saturated fluid may beused. Use of such fluids may enhance cavitation of an occlusion, helpprevent unwanted tissue damage and/or the like. Such fluids aredescribed, for example, in U.S. Pat. Nos. 6,676,900, 6,622,542,6,613,280, 6,607,698, 6,605,217, 6,602,468, 6,602,467, 6,596,235,6,582,387, 6,576,807, 6,558,502, 6,555,059, 6,533,766, 6,454,997,6,387,324, 6,346,192, 6,315,754, 6,248,087, 6,235,007, 6,180,059,6,142,971, 6,123,698, 6,030,357, 5,976,119, 5,957,889, 5,893,838 and5,797,876, which are hereby incorporated by reference. In anotherembodiment, a mixture of contrast dye and saline may be used to achievethe same or similar results.

With reference now to FIGS. 4A-4C, one embodiment of a proximal portionof a vibrational transmission member 140 and a transition connector 252for connecting to a vibrational transducer is shown. Transitionconnector 252 includes a proximal connection member 210 for attaching toa vibrational transducer, such as an ultrasound transducer. Connector252 also includes a tapered distal portion 212 with a bore 216 extendinginto it from the distal end of connector 252. The proximal end ofvibrational transmission member 140 extends into bore 216, and distalportion 212 is crimped down onto the proximal end of transmission member140, using a crimping device 214 (crimping motion designated byhollow-tipped arrows in FIG. 4A). As shown in FIG. 4A, crimping force isapplied to tapered distal portion 212 via crimping device 214 orientedparallel with a longitudinal axis along the length of ultrasoundtransmission member 140. Thus, crimping device 214 contacts and beginsapplying force to a proximal end of distal portion 212 before contactingand applying force to a distal end of distal portion 212.

By crimping distal portion 212 using the technique just described, andreferring now to FIG. 4B, greater crimping force (solid-tipped arrows)is applied by distal portion 212 against an attached proximal-mostportion of transmission member 140 than is applied against animmediately adjacent more-distal portion of transmission member 140(hollow-tipped arrows). By applying this variable crimping force totransmission member 140, distal portion 212 of transition connector 252absorbs vibrational motion occurring near its distal end, thus reducingstress on the transmission member 140 at the point where it enters bore216. This stress reduction helps reduce wear and tear on transmissionmember 140, thus extending the useful life of the catheter device.

FIG. 4C shows an attached vibrational transmission member 140 andtransition connector 252. In various embodiments, transition connector252 may be a one-piece member or may alternatively include two or morepieces attached together. Proximal connection member 210 may include anysuitable attachment means for removably attaching transition connector252 to a transducer, such as but not limited to threads for screwinginto complementary threads on the transducer or a snap-fit connector.

With reference now to FIGS. 5A-5C, an alternative embodiment of atransition connector 352 includes a proximal connection member 210 and adistal portion 312 having a bore 216, a proximal step 322 and a distalstep 320. Proximal step 322 has a greater outer diameter than distalstep 320. Thus, when crimping force is applied to distal portion 312, asshown in FIG. 5A (hollow-tipped arrows), crimping device 214 contactsonly proximal step 322. Force is indirectly applied to distal step 320through proximal step 322, but as depicted in FIG. 5B, greater force(solid-tipped arrows) is applied to transmission member 140 via proximalstep 322 than via distal step 320. This variable crimping force allowsdistal step 320 to absorb vibrations of transmission member 140, thusreducing wear and tear.

FIG. 5C is a perspective view of the assembled transition connector 352and vibrational transmission member 140.

Referring now to FIGS. 6A-6C, an alternative embodiment of a transitionconnector 452 includes a proximal connection member 210 and a distalportion 412 having a bore 416 with a widened distal opening 418.Referring to FIG. 6A, to attach transition connector 452 to vibrationaltransmission member 140, crimping force (hollow-tipped arrows) isapplied via crimping device 214 oriented approximately along alongitudinal axis of the catheter. As shown in FIG. 6B, in thisembodiment, crimping force closes widened distal opening 418 aroundtransmission member 140. The crimping process thus applies less force(hollow-tipped arrows) against transmission member 140 via thedistal-most part of distal portion 412 than via an immediately adjacent,more proximal part of distal portion (solid-tipped arrows). Again, thisvariable crimping force allows for vibrational absorption at the distalend of transition connector 452, thus reducing stress on vibrationaltransmission member.

FIG. 6C is a perspective view of the assembled transition connector 452and vibrational transmission member 140.

Referring now to FIGS. 7A-7C, an alternative embodiment of a transitionconnector 462 includes a proximal connection member 210 and a distalportion 472 having a bore 478 that widens from its proximal terminus 476to a widened distal opening 474. The widened distal opening 474 forms aspace between opening 474 and transmission member 140. Referring to FIG.7A, to attach transition connector 462 to vibrational transmissionmember 140, crimping force (hollow-tipped arrows) is applied viacrimping device 214 oriented approximately along a longitudinal axis ofthe catheter. As shown in FIG. 7B, crimping force closes widened distalopening 474 around transmission member 140. The crimping process thusapplies less force (hollow-tipped arrows) against transmission member140 via the distal-most part of distal portion 472 than via animmediately adjacent, more proximal part of distal portion (solid-tippedarrows). Again, this variable crimping force allows for vibrationalabsorption at the distal end of transition connector 462, thus reducingstress on vibrational transmission member.

With reference now to FIGS. 8A-8C, an alternative embodiment of atransition connector 542 includes a proximal connection member 210 and adistal portion 512 having a bore 216. Referring to FIG. 8A, to attachtransition connector 542 to vibrational transmission member 140,crimping force is applied via a distal crimping member 532 a(hollow-tipped arrows) and a proximal crimping member 532 b. Crimpingmembers 532 may be part of one crimping device but controlledseparately, or alternatively they may be two separate devices. In analternative embodiment, one crimping member 532 may be used but appliedsequentially to proximal and distal parts of distal portion 512. In anycase, the force applied to distal portion 512 via proximal crimpingmember 532 b (solid-tipped arrows) is greater than the force applied todistal portion 512 via distal crimping member 532 a (hollow-tippedarrows).

As shown in FIG. 8B, the variably applied force (solid-tipped andhollow-tipped arrows) causes distal portion 512 to be more compressednear its proximal end, thus forming a proximal step 516 with a smallerouter diameter and a distal step 514 with a greater outer diameter. Inturn, more crimping force is applied against transmission member 140 byproximal step 516 than by distal step 514, thus allowing for vibrationalabsorption by distal step 514.

FIG. 8C is a perspective view of the assembled transition connector 542and vibrational transmission member 140, showing proximal step 516 anddistal step 514 of distal portion 512.

Although the invention has been described above with specific referenceto various embodiments and examples, it should be understood thatvarious additions, modifications, deletions and alterations may be madeto such embodiments without departing from the spirit or scope of theinvention. Accordingly, it is intended that all reasonably foreseeableadditions, deletions, alterations and modifications be included withinthe scope of the invention as defined in the following claims.

1. A vibrational catheter for disrupting obstructions in lumens such asblood vessels, the catheter comprising: an elongate flexible catheterbody having a proximal end, a distal end and at least one lumenextending longitudinally therethrough; a vibrational transmission memberextending longitudinally through the lumen of the catheter body andhaving a proximal end and a distal end; and a transition connectorattached to the proximal end of the vibrational transmission member forcoupling the transmission member with a vibrational energy source, thetransition connector comprising a bore into which the proximal end ofthe vibrational transmission member extends, wherein the proximal end ofthe vibrational transmission member is attached within the bore of thetransition connector with variable attachment forces such that thetransition connector exerts a lowest amount of attachment force on anattached distal-most portion of the vibrational transmission memberhoused within the bore.
 2. A vibrational catheter as in claim 1, whereinthe vibrational energy source comprises a transducer.
 3. A vibrationalcatheter as in claim 2, wherein transducer comprises an ultrasoundtransducer.
 4. A vibrational catheter as in claim 1, wherein thetransition connector comprises multiple pieces attached together.
 5. Avibrational catheter as in claim 1, wherein the transition connectorcomprises a one-piece configuration.
 6. A vibrational catheter as inclaim 1, wherein the transition connector comprises threads, which arecomplementary to threads on the vibrational energy source.
 7. Avibrational catheter as in claim 1, wherein the transition connectorcomprises a distal portion tapered proximally to distally, the distalportion extending from a proximal terminus of the bore to a distalopening of the bore.
 8. A vibrational catheter as in claim 7, whereinthe vibrational transmission member is attached within the bore bycrimping the tapered distal portion of the transition connector so as toapply greater crimping force to a wider, proximal part of the distalportion than to a narrower, distal part of the distal portion.
 9. Avibrational catheter as in claim 1, wherein the transition connectorcomprises a distal portion comprising: a first stepped portion having afirst radius and extending distally from a proximal terminus of thebore; and a second stepped portion having a second radius smaller thanthe first radius and extending from a distal end of the first steppedportion to a distal opening of the bore.
 10. A vibrational catheter asin claim 9, wherein the vibrational transmission member is attachedwithin the bore by crimping the first stepped portion, thus applyinggreater crimping force to the first stepped portion than the secondstepped portion.
 11. A vibrational catheter as in claim 1, wherein thebore comprises: a first stepped portion having a first radius andextending distally from a proximal terminus of the bore; and a secondstepped portion having a second radius greater than the first radius andextending from a distal end of the first stepped portion to a distalopening of the bore.
 12. A vibrational catheter as in claim 11, whereinthe vibrational transmission member is attached within the bore bycrimping the transition connector, thus applying greater crimping forceto the first stepped portion than the second stepped portion.
 13. Avibrational catheter as in claim 111, wherein a space exists between thetransmission member and the second stepped portion of the bore beforecrimping, and the space closes during crimping.
 14. A vibrationalcatheter as in claim 1, wherein the bore is tapered from a larger innerdiameter at a distal opening of the bore to a smaller inner diameter ata proximal terminus of the bore.
 15. A vibrational catheter as in claim14, wherein the vibrational transmission member is attached within thebore by crimping the transition connector, thus applying greatercrimping force at the proximal terminus of the bore than at the distalopening.
 16. A vibrational catheter as in claim 14, wherein a spaceexists between the transmission member and inner diameter of the distalopening of the bore before crimping, and the space closes duringcrimping.
 17. A vibrational catheter for disrupting obstructions inlumens such as blood vessels, the catheter comprising: an elongateflexible catheter body having a proximal end, a distal end and at leastone lumen extending longitudinally therethrough; a vibrationaltransmission member extending longitudinally through the lumen of thecatheter body and having a proximal end and a distal end; and atransition connector comprising: a proximal connection member forattaching the transition connector to the vibrational energy source; anda bore having an opening in a distal end of, and extending into, thetransition connector, for accepting the proximal end of the vibrationaltransmission member, wherein the proximal end of the vibrationaltransmission member is attached within the distal bore of the transitionconnector such that the transition connector exerts a greater amount ofattachment force on an attached proximal-most portion of thetransmission member than on an adjacent portion of the transmissionmember immediately distal to the proximal-most portion.
 18. Avibrational catheter as in claim 17, wherein the vibrational energysource comprises a transducer.
 19. A vibrational catheter as in claim18, wherein transducer comprises an ultrasound transducer.
 20. Avibrational catheter as in claim 17, wherein the transition connectorcomprises multiple pieces attached together.
 21. A vibrational catheteras in claim 17, wherein the transition connector comprises a one-piececonfiguration.
 22. A vibrational catheter as in claim 17, wherein theproximal connection member of the transition connector comprisesthreads, which are complementary to threads on the vibrational energysource.
 23. A vibrational catheter as in claim 17, wherein thetransition connector comprises a distal portion tapered proximally todistally, the distal portion extending from a proximal terminus of thebore to the opening of the bore.
 24. A vibrational catheter as in claim23, wherein the vibrational transmission member is attached within thebore by crimping the tapered distal portion of the transition connectorso as to apply greater crimping force to a wider, proximal portion ofthe distal portion than to a narrower, distal portion of the distalportion.
 25. A vibrational catheter as in claim 17, wherein thetransition connector comprises a distal portion comprising: a firststepped portion having a first radius and extending distally from aproximal terminus of the bore; and a second stepped portion having asecond radius smaller than the first radius and extending from a distalend of the first stepped portion to the distal opening of the bore. 26.A vibrational catheter as in claim 25, wherein the vibrationaltransmission member is attached within the bore by crimping the firststepped portion, thus applying greater crimping force to the firststepped portion than the second stepped portion.
 27. A vibrationalcatheter as in claim 17, wherein the bore comprises: a first steppedportion having a first radius and extending distally from a proximalterminus of the bore; and a second stepped portion having a secondradius greater than the first radius and extending from a distal end ofthe first stepped portion to the distal opening of the bore.
 28. Avibrational catheter as in claim 27, wherein the vibrationaltransmission member is attached within the bore by crimping thetransition connector, thus applying greater crimping force to the firststepped portion than the second stepped portion.
 29. A vibrationalcatheter as in claim 27, wherein a space exists between the transmissionmember and the second stepped portion of the bore before crimping, andthe space closes during crimping.
 30. A vibrational catheter as in claim17, wherein the bore is tapered from a larger inner diameter at a distalopening of the bore to a smaller inner diameter at a proximal terminusof the bore.
 31. A vibrational catheter as in claim 30, wherein thevibrational transmission member is attached within the bore by crimpingthe transition connector, thus applying greater crimping force at theproximal terminus of the bore than at the distal opening.
 32. Avibrational catheter as in claim 30, wherein a space exists between thetransmission member and inner diameter of the distal opening of the borebefore crimping, and the space closes during crimping.
 33. A method formaking a vibrational catheter for disrupting obstructions in lumens suchas blood vessels, the method comprising: inserting a proximal end of avibrational transmission member into a bore in a transition connector ofthe catheter; and crimping at least part of the transition connector toattach the proximal end of the vibrational transmission member withinthe bore, wherein a variable amount of crimping force is applied toattach the transmission member within the bore, such that the transitionconnector exerts a lowest amount of attachment force on an attacheddistal-most portion of the vibrational transmission member housed withinthe bore.
 34. A method as in claim 33, wherein crimping is performedwith a crimping tool having a contact surface parallel with thevibrational transmission member, and wherein the greater amount ofcrimping force is applied via a shaped portion of the transitionconnector overlying the bore.
 35. A method as in claim 33, whereincrimping is performed with a crimping tool having a contact surfaceparallel with the vibrational transmission member, and wherein thegreater amount of crimping force is applied via a shaped bore.
 36. Amethod as in claim 33, wherein crimping is performed with a taperedcrimping tool having a contact surface that contacts a proximal portionof the transition connector overlying the bore before contacting a moredistal portion of the transition connector overlying the bore.
 37. Amethod as in claim 33, wherein crimping is performed with two or morecrimping members, a more proximal crimping member applying greater forcethan a more distal crimping member.
 38. A method as in claim 33, whereincrimping comprises: crimping a first portion of the transition connectoroverlying the proximal-most portion of the transmission member with acrimping tool; moving the crimping tool distally along the transitionconnector; and crimping a second portion of the transition connectoroverlying the adjacent portion of the transmission member.
 39. A methodfor making a vibrational catheter for disrupting obstructions in lumenssuch as blood vessels, the method comprising: inserting a proximal endof a vibrational transmission member into a bore in a transitionconnector of the catheter; and crimping at least part of the transitionconnector to attach the proximal end of the vibrational transmissionmember within the bore, wherein the proximal end of the vibrationaltransmission member is attached within the distal bore of the transitionconnector such that the transition connector exerts a greater amount ofattachment force on a attached proximal-most portion of the transmissionmember than on an adjacent portion of the transmission memberimmediately distal to the proximal-most portion.
 40. A method as inclaim 39, wherein crimping is performed with a crimping tool having acontact surface parallel with the vibrational transmission member, andwherein the greater amount of crimping force is applied via a shapedportion of the transition connector overlying the bore.
 41. A method asin claim 39, wherein crimping is performed with a crimping tool having acontact surface parallel with the vibrational transmission member, andwherein the greater amount of crimping force is applied via a shapedbore.
 42. A method as in claim 39, wherein crimping is performed with atapered crimping tool having a contact surface that contacts a proximalportion of the transition connector overlying the bore before contactinga more distal portion of the transition connector overlying the bore.43. A method as in claim 39, wherein crimping is performed with two ormore crimping members, a more proximal crimping member applying greaterforce than a more distal crimping member.
 44. A method as in claim 39,wherein crimping comprises: crimping a first portion of the transitionconnector overlying the proximal-most portion of the transmission memberwith a crimping tool; moving the crimping tool distally along thetransition connector; and crimping a second portion of the transitionconnector overlying the adjacent portion of the transmission member.